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Registered

Looks like my A/C might need to be recharged soon and I was thinking of coverting from the R12 to the R134 and was wondering if anyone has done this before and if they may have any tips? I know I can get the conversion kit at autozone or wally mart fairly cheap but other then just swapping the connection and taking out the old R12 and replaceing it with R134 is there anything else to it?

Registered

The write up was talking about it being a replacement which made we wonder if I had to drain the old stuff. So if all I need is to recharge I can add one can and I should be good no need to drain, vaccum lines out then replace?

96Fleetwood thank you so much! Finally someone that actually help me out.

Auto Enthusiast

The law requires all the R-12 to be evacuated and permanent freeze-12 fittings to be installed, but I just added the freeze-12 to the existing R-12 with no issues. This isn't recommended. So to do it right, I would evacuate all the R12 out, because the freeze 12 is a mixture of 134 and 12.

Cadillac Technician

One of the reasons systems should be retrofit properly and NOT topped off is that if you take your car to a service center later and they hook up to your car your laziness could cost you a substantial amount of money.
When I service A/C systems, one of the steps I take is to recover your refrigerant to see how much is in your car. If I recover contaminated refrigerant into my machine and ruin 20 pounds of good refrigerant there is going to be a problem. Most modern machines have a built in identifier that stops that type of contamination from happening but old R-12 machines usually don't.
It costs a bundle of money to deal with problems like that and many shops will pass that expense right on to the person who is responsible.

If you must use a different refrigerant, follow the instructions to properly retrofit your car to use that refrigerant, that includes fittings and labels to identify what you have done.

You can readily purchase a kit to retrofit to R-134a that has fittings, oil, and most things necessary to do so. Be sure to find and fix any leaks before you charge the system.

Registered

But pulling out good R12 or R134a for no reason is illegal (and immoral), and nasty fines by EPA ($10K and up per violation), if you pull it out and refill and charge (as in $$) for new R12 or R134a to be put back in. You cannot remove good freon, and put it back in (or even the old freon) and charge for it legally. Recovering freon just to "see how much" is illegal unless it is all put back in and not charged for. Be careful on how that is done. The list of dealers and shops that are fined (for many many reasons including that) are long listed at EPA.gov, take a look. There is no reason to pull freon out ever to see how much is in there, that is why GM has very detailed pressure charts in the FSM. You fill by weight, but maintaining the pressures are quite important also. I won't take my car to a shop that would ever think of removing it just to see what is in there.

If a shop ever did that to my car I would rip them up one side and down the other.

One of the reasons systems should be retrofit properly and NOT topped off is that if you take your car to a service center later and they hook up to your car your laziness could cost you a substantial amount of money.
When I service A/C systems, one of the steps I take is to recover your refrigerant to see how much is in your car. If I recover contaminated refrigerant into my machine and ruin 20 pounds of good refrigerant there is going to be a problem. Most modern machines have a built in identifier that stops that type of contamination from happening but old R-12 machines usually don't.
It costs a bundle of money to deal with problems like that and many shops will pass that expense right on to the person who is responsible.

If you must use a different refrigerant, follow the instructions to properly retrofit your car to use that refrigerant, that includes fittings and labels to identify what you have done.

You can readily purchase a kit to retrofit to R-134a that has fittings, oil, and most things necessary to do so. Be sure to find and fix any leaks before you charge the system.

1. Many refrigerants, including R-401A (made by DuPont), R-401B (DuPont), R-409A (Elf Atochem), Care 30 (Calor Gas), Adak-29/Adak-12 (TACIP Int'l), MT-31 (Millenia Tech), and ES-12R (Intervest), have not been submitted for review in motor vehicle air conditioning, and it is therefore illegal to use these refrigerants in such systems as an alternative to CFC-12.
2. See text for details on legality of use according to status
* Acceptable Subject to Use Conditions
* regarding fittings, labeling, no drop-in, and compressor shutoff switches. Unacceptable; illegal for use as a CFC-12 substitute in motor vehicle air conditioners

Cadillac Technician

I am not sure if you are trying to accuse me of something there or not but I'll answer some of what I think needs to be addressed based on that post.

Charging the whole system by weight is much more precise than using a pressure table because of variations in ambient temperatures and humidity.
The system is designed to run on a given quantity of refrigerant.
I am not taking refrigerant out and sending people away with none, that would be stealing... not to mention stupid.
Many times I get systems that have been charged by pressure and they don't work properly because they have been overfilled.

As for the billing, I let them handle all that up front and I abide by whatever policy my company has.

I don't just drive down the road and steal refrigerant, if someone brings me a car with the system not working I need to know if it is low or overcharged or whatever. Over the last 15 years or so I have fixed many an A/C system without ripping anyone off and my customers are quite satisfied with my services.
I have been MACS certified in refrigerant handling since about 1994 and am well versed in finding and fixing exactly what is wrong on the first visit.
I know everyone can't be a pro and have the equipment to do the job that I can do, I just wanted to offer some constructive advice to prevent someone from ending up paying a huge bill when their "drop in" mixture screws up someone's equipment and they get hit with a hazmat bill and charged for the lost refrigerant in the machine they contaminated. I think R-12 is going for about what.... $50-$60 a pound these days? Multiply that by 20 or so and it is more than I have to throw away.

GM has a detailed procedure on how to diagnose and repair A/C systems.
I follow that.

Registered

No, not accusing you at all, sorry, it is hard to explain this point. I can't find the EPA's comments on it, but they are stiff. But basically you bring your car into a shop, they pull the freon "to see what you have", and then recharge it, charging you for the full amount of the freon (of course, NEW freon), and you go out the door with a hefty bill, now perfectly good freon was removed for the wrong reason. For an average 2.5-3 lb system @ $60/lb, that is quite painful, or my Suburban at nearly 4 lbs, that is $240ish, no labor charged. The EPA is VERY harsh on this practice, good freon is NOT to be removed just to remove it. It is illegal to remove freon in this manner. If you remove it, measure and reinstall, that is perfectly fine, but you cannot charge the customer for their own freon. So if the front office IS doing this, then you could be the scapegoat, be cautious.

My AC in my 94 runs fantastic (even for R134a), what I found is the orifice filter plugged last year, causing skyrocketing pressures (found out the hard way there is a popoff overpressure valve) and I ended up having to flush the system to get out all the junk. The OEM compressor died (for unk reasons, long before I bought the car) and in 9 months, the replacement went belly up. So my car is on compressor #4. It works fine now. But I still got a lot of junk in the filter/screen, enough to plug it up good.

Having a good competent AC guy is key. AC isn't complicated at all, but if one doesn't understand the basics, leave it alone or learn.... I did, it was well worth the learning! One of these days I just need to get my cert, but I don't have the equipment at home to do it.....

Registered

If I could find a shop that would recharge my system for $50-$60 instead of buying this Freeze12 for $40 then I would go there in a second cause I would not need a full pound. The problem here is that shops charge way to much $$ for a simple charge especially R-12! This is the reason people try to find a cheaper solution to fix this problem and converting to the R-134 would be a better move then continuing to use the R-12 but if I can fix my recharge with 1 can of Freeze-12 I am very tempted instead of dropping $40 for the Freeze-12 kit or the R-134a kit.

Now saying this I am not accusing anyone of anything just stating how it is around here so please don't take offense ewill3rd.

Cadillac Technician

I was thinking a moment ago about it, and the real reason I do it that way is because the machine charges by weight and not by pressure.
I can't tell it to charge to a certain pressure so I have to find out how much is in it so I can know how much to add.
Back in the day when I used a manifold set and a can tap I could add and watch the pressures but with the ACR 2000 that GM has us use we can only charge by weight.

The refrigerant handling certification test is available at ASE's website. It is an open book test that costs like $15 bucks and then you can buy stuff to do whatever you want to your A/C system.
I just try to do things in a more factory fashion because I am a factory tech.

I don't have a problem with changing refrigerants but as I said, please do it properly with the fittings and decals as required by law.

Cadillac Technician

I know a couple of things like R134 won't carry the mineral oil used in R12 systems. From what studying I have done, if you drop 134 into a 12 system without adding oil it will lock up. Most articles I have seen indicate that the mineral oil will just end up sitting in the bottom of the accumulator after time and be harmless but you have to put PAG oil in using the proper amount to keep the compressor lubricated.
Another reason for replacing the accumulator.

I think the primary thing that it does "bad" is contaminate the equipment.
Obviously if refrigerants are blends of 134 and other stuff there isn't going to be a chemical reaction but speaking for our equipment, it has a refrigerant identifier in it, if it detects 12 in a 134 system it will stop working.
The identifier looks for air, HCs, and foreign refrigerants and if it doesn't see over 99% 134 it locks up and spits out what it tasted.

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